Many types of spinal irregularities can cause pain, limit range of motion, or injure the nervous system within the spinal column. These irregularities can result from, without limitation, trauma, tumor, disc degeneration, and disease. Often, these irregularities are treated by immobilizing a portion of the spine. This treatment typically involves affixing a plurality of fixation devices to one or more vertebrae and connecting the devices to an elongate rod that generally extends in the direction of the axis of the spine.
Treatment for these spinal irregularities often involves using a system of fixation devices to attain stability between spinal segments. Instability in the spine can create stress and strain on neurological elements, such as the spinal cord and nerve roots. In order to correct this, implants of certain stiffness may be implanted to restore the correct alignment and portion of the vertebral bodies. In many cases, a fixation device along with a vertical solid member can help restore spinal elements to a pain free situation, or at least may help reduce pain or prevent further injury to the spine.
Typically, fixation devices may include a bone fastener (e.g., bone screw, hook, etc.) for coupling the fixation device to vertebra. Fixation devices further may include a coupling element (e.g., a tulip element) for coupling the bone fastener to the vertical solid member (e.g., elongate rod). Clamp and/or wedge elements may be used to secure the bone fastener in the coupling element. A locking cap may be used to secure the rod in the coupling element. In order for the elements of the fixation device to be secured, the rod may need to be seated firmly in the coupling element. A variety of methods and instruments may be used to maximize engagement between the rod and the coupling element and attachment of the fixation devices.
Traditionally, these types of spinal devices were installed via open-back surgery. This type of procedure tended to cause extensive trauma to the patient, resulting in long and painful recovery times. In recent years, a shift has been made toward minimally invasive surgery (MIS) techniques. In minimally invasive surgery, the surgeon makes small incisions and uses special tools to insert devices, observe progress of the operation, and perform other activities in the surgical site. Minimally invasive surgical techniques frequently result in much less injury to the patient and improved healing and recovery times. In a minimally invasive procedure, however, it may be more difficult for the physician to insert and secure the fixation devices, maneuver the rod, or the like. There is a need for improved tools and instrumentation, for example, suitable for use in minimally invasive procedures.